[mellanox] Implement PSU related APIs based on the new platform API (#2460)

* Implement part of PSU related APIs including get_status(), get_presence()

Signed-off-by: Kevin Wang <kevinw@mellanox.com>

platform/mellanox/mlnx-platform-api.mk

@@ -0,0 +1,7 @@
+# SONIC_PLATFORM_API_PY2 package
+
+SONIC_PLATFORM_API_PY2 = mlnx_platform_api-1.0-py2-none-any.whl
+$(SONIC_PLATFORM_API_PY2)_SRC_PATH = $(PLATFORM_PATH)/mlnx-platform-api
+$(SONIC_PLATFORM_API_PY2)_PYTHON_VERSION = 2
+SONIC_PYTHON_WHEELS += $(SONIC_PLATFORM_API_PY2)
+

platform/mellanox/mlnx-platform-api/setup.py

@@ -0,0 +1,30 @@
+from setuptools import setup
+
+setup(
+    name='mlnx-platform-api',
+    version='1.0',
+    description='SONiC platform API implementation on Mellanox platform',
+    license='Apache 2.0',
+    author='SONiC Team',
+    author_email='linuxnetdev@microsoft.com',
+    url='https://github.com/Azure/sonic-buildimage',
+    maintainer='Kevin Wang',
+    maintainer_email='kevinw@mellanox.com',
+    packages=[
+        'sonic_platform_api',
+    ],
+    classifiers=[
+        'Development Status :: 3 - Alpha',
+        'Environment :: Plugins',
+        'Intended Audience :: Developers',
+        'Intended Audience :: Information Technology',
+        'Intended Audience :: System Administrators',
+        'License :: OSI Approved :: Apache Software License',
+        'Natural Language :: English',
+        'Operating System :: POSIX :: Linux',
+        'Programming Language :: Python :: 2.7',
+        'Topic :: Utilities',
+    ],
+    keywords='sonic SONiC platform-api PLATFORM-API',
+)
+

platform/mellanox/mlnx-platform-api/sonic_platform_api/chassis.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+
+#############################################################################
+# Mellanox
+#
+# Module contains an implementation of SONiC Platform Base API and
+# provides the Chassis information which are available in the platform
+#
+#############################################################################
+
+import sys
+
+try:
+    from sonic_platform_base.chassis_base import ChassisBase
+    from sonic_platform_api.psu import Psu
+except ImportError as e:
+    raise ImportError (str(e) + "- required module not found")
+
+MLNX_NUM_PSU = 2
+
+class Chassis(ChassisBase):
+    """Platform-specific Chassis class"""
+    def __init__(self):
+        ChassisBase.__init__(self)
+        for index in range(MLNX_NUM_PSU):
+            psu = Psu(index)
+            self._psu_list.append(psu)
+

platform/mellanox/mlnx-platform-api/sonic_platform_api/psu.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python
+
+#############################################################################
+# Mellanox
+#
+# Module contains an implementation of SONiC Platform Base API and
+# provides the PSUs status which are available in the platform
+#
+#############################################################################
+
+import os.path
+
+try:
+    from sonic_platform_base.psu_base import PsuBase
+except ImportError as e:
+    raise ImportError (str(e) + "- required module not found")
+
+psu_list = []
+
+class Psu(PsuBase):
+    """Platform-specific Psu class"""
+    def __init__(self, psu_index):
+        global psu_list
+        PsuBase.__init__(self)
+        # PSU is 1-based on Mellanox platform
+        self.index = psu_index + 1
+        psu_list.append(psu_index)
+        self.psu_path = "/var/run/hw-management/thermal/"
+        self.psu_oper_status = "psu{}_pwr_status".format(self.index)
+        self.psu_presence = "psu{}_status".format(self.index)
+        if os.path.exists(os.path.join(self.psu_path, self.psu_presence)):
+            self.presence_file_exists = True
+        else:
+            self.presence_file_exists = False
+
+    def get_status(self):
+        """
+        Retrieves the operational status of power supply unit (PSU) defined
+
+        Returns:
+            bool: True if PSU is operating properly, False if not
+        """
+        status = 0
+        try:
+            with open(os.path.join(self.psu_path, self.psu_oper_status), 'r') as power_status:
+                status = int(power_status.read())
+        except (ValueError, IOError):
+            status = 0
+
+        return status == 1
+
+    def get_presence(self):
+        """
+        Retrieves the presence status of power supply unit (PSU) defined
+
+        Returns:
+            bool: True if PSU is present, False if not
+        """
+        status = 0
+        if self.presence_file_exists:
+            try:
+                with open(os.path.join(self.psu_path, self.psu_presence), 'r') as presence_status:
+                    status = int(presence_status.read())
+            except (ValueError, IOError):
+                status = 0
+        else:
+            status = self.index in psu_list
+
+        return status == 1
+

platform/mellanox/rules.mk

@@ -3,6 +3,7 @@ include $(PLATFORM_PATH)/fw.mk
 include $(PLATFORM_PATH)/mft.mk
 include $(PLATFORM_PATH)/mlnx-sai.mk
 include $(PLATFORM_PATH)/hw-management.mk
+include $(PLATFORM_PATH)/mlnx-platform-api.mk
 include $(PLATFORM_PATH)/docker-syncd-mlnx.mk
 include $(PLATFORM_PATH)/docker-syncd-mlnx-rpc.mk
 include $(PLATFORM_PATH)/docker-orchagent-mlnx.mk

rules/docker-platform-monitor.mk

@@ -6,6 +6,7 @@ $(DOCKER_PLATFORM_MONITOR)_DEPENDS += $(LIBSWSSCOMMON) $(PYTHON_SWSSCOMMON)
 $(DOCKER_PLATFORM_MONITOR)_PYTHON_DEBS += $(SONIC_LEDD) $(SONIC_XCVRD) $(SONIC_PSUD)
 $(DOCKER_PLATFORM_MONITOR)_PYTHON_WHEELS += $(SONIC_PLATFORM_COMMON_PY2)
 $(DOCKER_PLATFORM_MONITOR)_PYTHON_WHEELS += $(SWSSSDK_PY2)
+$(DOCKER_PLATFORM_MONITOR)_PYTHON_WHEELS += $(SONIC_PLATFORM_API_PY2)
 $(DOCKER_PLATFORM_MONITOR)_LOAD_DOCKERS = $(DOCKER_CONFIG_ENGINE)
 
 SONIC_DOCKER_IMAGES += $(DOCKER_PLATFORM_MONITOR)